Centrifugal pump



Oct.. 7, 1941. c. H. WARMAN 2,258,527

CENTRIFUGAL PUMP Filed Dec. 29, 1939 INVENTOR.

* j ww'm KM Patented Oct. 7, 1941 CENTRIFUGAL PUMP Charles Harold Warman, Kalgoorlie, Western I Australia, Australia Application December 29, 1939, Serial No. 311,680 In Australia January 10, 1939 3 Claims.

This invention relates to improvements in centrifugal pumps: more particularly to improvements in pumps for use in pumping corrosive fluids or fluids with abrasive solids in suspension. A great difficulty in puming fluids of this nature is to prevent wear and consequent enlargement of the clearances between the rotary and stationary members, which will result in leakage, slippage, and serious loss of head and efliciency.

The chief object of my invention is to provide improved durable and efilcient sealing means for preventing the passage of fluids between the stationary and rotary members. Another object is to provide a pump which is simple, easily ac-.

cessible, and with few parts subject to corrosion and/or abrasion by the fluids being pumped.

My invention is illustrated more or less diagrammatically in the accompanying drawing,

wherein: v

Fig. 1 is a part vertical axial section.

Fig. 2 is a section on a smaller scale on the line 2-2 ofFig. 1.

Fig. 3 is an-elevation of the expeller member, also on a smaller scale.

Like parts are illustrated by like characters throughout the specification and'drawing.

Referring to the drawing, I!) generally indicates a frame. It supports a bearing housing H,

of any suitable design for rotatably mounting the spindle |2. The frame has attached a vertical portion or frame plate l3, having a circular recess for a renewable resilient liner l4, and an annular flange projecting from one side of the casing IS. The casing is held in place on its plane surface against the resilient liner by studs l6, screwed into the frameplate l3, and passing through the coverplate H; which also has a circular recess for a renewable resilient liner l8. Two of the studs l6, diametrically opposite each other, may each have an intermediate nut, not shown, which tightens against the lugs (also not shown)- on the casing l5, and servesto hold it in position when the coverplate H is removed.

An impeller I9 is situated concentrically within the casing |5,- and has an axial intake opening and peripheral discharge ports. It has -a boss l9 passing with working clearance through a central aperture in the liner M, such boss being'provided with a taper bore seating on the tapered portion of the spindle l2 and remov- I frame plate viewed as in Fig. 2) is such that the setscrew tends to screw into the spindle I! when the, pump is in operation. On each of its outer faces, the impeller I9 is provided with a plurality of projections or vanes 2|, outwardly conforming with suitable working clearance to the liners l4 and I8 respectively. The casing I5 is provided with an annular re- .cess 22, of constant cross-section, from which the outlet branch '23 develops tangentially and upwardly diverges to give a circular cross-section at the outlet flange. This flange has an annular groove 23' adapted to receive a pack: ing ring, and delivery piping may be attached in any suitable manner.

Provided on the coverplate I1, is the axial intake branch 24, having a flange of any suitable design for attachment of the inlet piping. The renewable resilient liner l8 has an axial tubular ortion |8' adapted to fitcl sely inside the intake branch 24, to prevent wear by the material flowing into the pump. An annular axial inner tubular projection or extension I8 of the liner l8 has its outer cylindrical surface conforming to the vanes 2| with suitable working clearance. This serves to direct the flow of material intothe intake opening of the impeller cylindrical liner 26, both of wh ich position by beingclamped between-tn able resilient liner l4 and a shoulder 31 l3. An inwardly projecting diaphragm 38, part of the cylindrical liner 26, has a central circular aperture, through which the rotating members pass with ample working clearance. It also has an extension on the diaphragm portion in the form of a -central projecting annular shoulder 39. The renewable resilient liner l4 consists of a rigid circular plate, having a central projecting tubular portion 40. It is completely covered with a resilient wear resistingmaterial, such as, for instance, soft rubber, which may be moulded about it. Its central aperture allows the impeller boss l9 to pass. through it with ample working clearance. To the outer cylindrical surface of the resilient covering on said projecting tubular portion 40 of the liner. I4, the vanes 2|, on the impellerv I9, conform with suitable working clearance.

Mounted on the spindle l2, and rotating with it, are an auxiliary impeller or expeller 21, a pliable elastic disc sealing member 28. a scaling disc follower 29, and a helical spring 30. This spring, being mounted in a state of compression between the fixed shaft collar 3| and the sealing disc follower 29, forces the expeller member 21 against the impeller boss IS, the sealing disc- 28 against the said expeller member, and

.forms a continuous circumferential seal with the conical surface of the die plate 25, when the 'spindle I2 is not rotating. When the spindle rotates at an appropriate speed, centrifugal force acting on the conical sealing'member 28 causes it to become less conical, so that it ceases to contact the die plate '25, and rubbing contact between the stationary and rotating members is avoided. Situated within and conforming with ample running clearance to the annular space between the diaphragm portion of the liner 26 and the liner I4, are the radial flange and the sloping expeller vanes 32, forming part of the expeller member 21. The expeller vanes project axially and overlap the annular shoulder on the diaphragm portion of the liner 26. A.

dowel or key 33, projecting from the spindle l2, and engaging a recess provided for it in the expeller 21, insures that the expeller will rotate with the shaft.

To facilitate the machining and manufacture of the impeller l9 and expeller 21, which are made of a hard material to withstand wear and abrasion, the portions which fit the spindle l2 are linedwith a soft non-corroding material 34 and 35, such as white metal, such lining also facilitating the removal of these members when their replacement is required.

The use and operation of my invention are as follows:

With the pump constructed as shown in the drawing, the impeller is caused to rotate in an anti-clockwise direction, and the fluid to be pumped permitted to flow into the impeller intake through the intake branch 24; Passing through the impeller discharge ports, the fluid has its pressure increased by centrifugal action to that within the casing 15, adjacent to the periphery of the impeller; On leaving the impeller, the fluid continues to rotate within the casing, developing further pressure with decrease of its kinetic energy, until it is discharged through the outlet branch 23 into a delivery pipe or the like.

Leakage of fluid discharged from the impeller back to the intake opening and at the point where the impeller boss passes through the liner M respectively, is almost entirely prevented by the centrifugal action on the fluid of the vanes 2| projecting from the sides of the impeller coacting with the projecting shoulders of the liners l8 and M respectively. These shoulders'direct the slippage fluid inwards in the path of the vanes 2|, which return it to the periphery of the impeller. Freedom from leakage, where the rotating members pass through the frame plate I3 is ensured when the pump is operating, by the expeller member 21 rotating within the space and the liner l4, and so creating"by ceiitfifugal action of the vanes 32 on the slippage fluid a pressure therein equal to that at the point where the impeller boss passes through the liner [4.

The annular shoulder, part of the liner 26, about pump acting to press said sealing member against the die plate. When rotating at the proper'operating speed, the more or less conical sealing member 28 is flattened out by centrifugal force and runs clear of the die plate.

Iam aware that centrifugal pumps are in use, or have been described, which have auxiliary impeller or expeller means for preventing by centrifugal action the leakage of fluid at the point where the impeller spindle enters the casing, and have also centrifugal means for sealing the clearance between the shaft and the casing when the pumpis inoperative. In every case, how-- ever, the auxiliary impeller or centrifugal sealing devices and the impeller spindle have been placed on the intake or suction side of the main impeller, where they are subjected to the pump intake head only, the path of entry of the fluid to the impeller being between the impeller and th centrifugal sealing means. My present invention differs basically from these pumps, in that the auxiliary centrifugal sealing means employed for preventing leakage of fluid where the impeller shaft enters the casing is on the side of the impeller opposite to its intake opening, and performs its duty of preventing leakage against the full pressure in the casin by cooperating with auxiliary vanes projecting from the side of the impeller opposite to its intake opening and adjacent to the point of entry to the casing of the impeller supporting means.

I am aware also that many centrifugal devices are in use, or have been described, which employ impellers having projecting auxiliary vanes on the side of the impeller adjacent to the point of entry to the casing of the impeller spindle, said vanes being peripherallyadjacent and exterior to cylindrical shoulders projecting from between the diaphragm portion of the liner 26 the casing. I make no claim to such devices, except in combination with separate auxiliary impeller means external to the main impeller chamber,' such that the combined centrifugal effect of the auxiliary vanes on the main impeller and the auxiliary impeller means is sufficient to give a fluid pressure equal to or greater than the fluid pressure within the main impeller chamber.

I claim:

1. A centrifugal pump comprising a casing having a main chamber and an auxiliary chamber therein, a spindle extending through said auxiliary chamber into the main chamber of said casing, an impeller arranged within said main chamber and fixed to one end of said spindle, a boss formed with said impeller, a renewable liner arranged within said casing between the main and auxiliary chambers thereof, an annular proection formed with said liner extending about said boss and having a running clearance therewith, an auxiliary impeller arranged within said auxiliary chamber, vanes formed with said auxliary impeller, and a cylindrical liner with an inwardly projecting diaphragm extending about 2,288,527 a a said'vanes with arunning clearance therebe- I tween. I

2. A centrifugal pump comprising a casing, a frame plate connected to said casing, a liner interposed between said frame plate and casing, one end oi said frame plate having a circular opening formed therein, a spindle extending through the circular opening of the said frame plate, an impeller arranged within said casing and fixed to one end of said spindle, a boss formed with said impeller and extending through said liner arranged between said frame plate and casins. an auxiliary impeller connected to said spindle and arranged adjacent one end of said boss, a cylindrical liner slidably arranged within said frame plate adjacent said auxiliary impeller and a circular die plate. with a central aperture having a running clearance with the spindle and.

slidably arranged adjacent said cylindrical liner within said frame plate.

3. A centrifugal pump comprising a casing having a main chamber and an auxiliary chamher therein, a spindle extending through said, auxiliary chamber into the main chamber of said casing, a dieplate forming the end of said auxiliary chamber remote from said main chamber, a central aperture in said die plate through which said spindle passes with running clearance, a pliable disc sealing member mounted on said spindle adjacent said die plate within said auxiliary chamber, said pliable disc sealing memher being adapted to be pressed in sealing contact with said die plate by fluid pressure within the auxiliary chamber when the pump is inoperative.

CHARLES HAROLD 

